Papers by Mohammad Hassan Vakili
Journal of Applied Electrochemistry, 2022
The synthesis and use of a suitable metal–organic framework (ZIF-67) as a sensory material for vo... more The synthesis and use of a suitable metal–organic framework (ZIF-67) as a sensory material for voltammetric measuring of silver(I) is the subject of this investigative work. In this regard, the size exclusion property of the ZIF-67 is coupled with the analytical voltammetry method and as a result, an efficient approach for measuring silver(I) has been obtained with appropriate selectivity and sensitivity. The detailed characterization of the synthesized ZIF-67 as well as the carbon paste electrode modified with it (Fourier transform-infrared spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy–energy-dispersive X-ray analysis, Brunauer–Emmett–Teller method, cyclic voltammetry, and impedance spectroscopy) indicates the exact synthesis of high-purity ZIF-67. Box–Behnken design has been used to optimize the conditions of preparation and operation of the sensor. There is a direct relationship between silver molarity in the enrichment solution and silver stripping current in the 1.0 × 10−10 to 2.5 × 10−7 molarity range. The detection limit was 2.5 × 10−11 M. Proper selectivity of this sensor greatly reduces mercury interference in silver measurement. When using the sensor to measure silver in real samples, results were obtained that agree with the results of the classical method of measuring silver.
Journal of Chemical and Petroleum Engineering, 2017
Butyl stearate as a phase change material was microencapsulated within melamine-formaldehyde resi... more Butyl stearate as a phase change material was microencapsulated within melamine-formaldehyde resin using emulsion polymerization. Morphology and thermal specification of produced microcapsules were studied by Fourier transform infrared spectroscopy, FT-IR, scanning electron microscopy, SEM, and Differential scanning calorimetry analysis, DSC. FT-IR spectra validated the existence of the butyl stearate in the core of microcapsules. SEM graphs showed that melamine formaldehyde polymer without core was spherical and almost uniform with an approximate size of 2µm and microcapsules of butyl stearate in melamine formaldehyde shell were also spherical with the average diameter of 4µm. DSC results showed that microencapsulation reduced the latent heat of melting and freezing of butyl stearate and increased melting point. The performance of the produced microcapsules was obtained 36.64%. Moreover, the efficiency of energy storage by the microcapsules was obtained about 40%. It was observed t...
Physical Chemistry Research, 2019
There is a great technical interest in solid-liquid equilibrium (SLE) of binary fatty acids. Main... more There is a great technical interest in solid-liquid equilibrium (SLE) of binary fatty acids. Mainly, these substances are used for the design, development, and operation of many industrial processes because of the application in many manufacturing fields such as the cosmetic, pharmaceutical and biotechnology industries. In this study, an approach is presented for binary fatty acid mixtures to estimate the melting temperatures as a function of mole fraction in the solid-liquid phase equilibrium. Derivation of the Wilson model was developed to predict the melting temperatures and latent heat to achieve eutectic points of capric acid, undecylic acid, pentadecylic acid, and margaric acid binary mixtures. The results showed that in the all binary mixtures, the eutectic point is near to a lighter compound except capric+undecylic acid because of lower melting temperature of undecylic acid than capric acid. Comparison of experimental and thermodynamic studies revealed the low deviations bet...
Physical Chemistry Research, 2015
In recent years there has been a great deal of attention paid by researchers in investigating ion... more In recent years there has been a great deal of attention paid by researchers in investigating ionic liquids (ILs) mainly due to the tremendous potential that ionic liquids have in reaction and separation technology. Sonic speed is an important thermodynamic property of ionic liquids (ILs) and always chosen as a source to determine other properties. A database for the sonic speed of pure ILs created by collecting experimental data from literature covering the period from 2005 to 2013 is presented. In this study, based on sonic speed experimental data, for the first time the relationship between boiling temperature, reduced temperature and pressure for 2198 data of 29 ionic liquids covering wide ranges of temperature, pressure, and sonic speed has been examined. In results, a 6-parameter model with ability for predicts the sonic speed of ionic liquids is presented. The obtained model has an average absolute relative deviation (AARD%) of 1.30%,a determination coefficient (R2) of 0.987,...
The main purpose of this studywas preparation of a pharmaceutical formulation with etoposide load... more The main purpose of this studywas preparation of a pharmaceutical formulation with etoposide loaded Poly Butyl Cyano Acrylate (PBCA) nanoparticles and evaluation of its effect on brain cancer. Etoposide loaded nanocarrier was synthesized using micro-emulsion polymerization method and characterized for shape morphology, particle size, zeta potential and drug-release properties. In the next step, BE (2)-C brain cell line was used to determine the rate of nanocarrieretoposide cytotoxicity. Etoposide loaded nanoparticles were characterized and size and zeta potential of nanoparticles containing drugs were measured as 225.3±21.7 nm and -26.3 ±1.5 mv, respectively. Drug loading and encapsulation values were estimated 8.7±0.15 and 97.3±2.1%, respectively. The release amount of drug from PBCA nanoparticles indicated the retention strength corresponding to the formulation. Cytotoxicity studies showed that the cell toxicity effect of drug loaded PBCA nanoparticles is almost two times higher t...
Ukrainian Journal of Ecology, 2018
One of the most important environmental problems is the pollution of surface and underground wate... more One of the most important environmental problems is the pollution of surface and underground waters with heavy metals. Since heavy metals are highly toxic, they are a serious threat to the environment and to the health of human and animals. In this study, the adsorption amount of heavy metals by activated-nano adsorbent sludge system has been investigated. The results show that by increasing the amount of nano-adsorbent in the activated-nano adsorbent sludge system, the percentage of heavy metal adsorption increases, with approximately 98% complete absorption.
Journal of Environmental Chemical Engineering, 2021
Molecular Simulation, 2020
A magnetic electrospun nanofibre was prepared and applied to load and release bovine serum albumi... more A magnetic electrospun nanofibre was prepared and applied to load and release bovine serum albumin (BSA). Fe 3 O 4 magnetic nanoparticles were prepared by chemical co-precipitation of ferric and ferrous salts and coated with polyvinyl alcohol/collagen electrospun nanofibre. Tripolyphosphate (TPP) and glutaraldehyde were used to stabilise nanoparticles within the electrospun nanofibres. It was found from scanning electron microscopy graphs that TPP is more suitable than glutaraldehyde and a network of relatively tall and perfectly uniform fibres with smooth surface can be produced and magnetic nanoparticles in their smallest size are distributed all over the fibres network without any agglomeration. BSA protein was loaded in magnetic nanofibres and its releasing under magnetic field and in the absence of magnetic field was studied using the Bradford assay method. The magnetic nanofibres completely changed the structure and formed pores and cracks under the magnetic field and then released BSA after 3 h, about 12 times higher than its releasing in the absence of magnetic field.
Journal of Pipeline Systems Engineering and Practice, 2019
AbstractTwo types of composites, fiberglass/epoxy and fiberglass/polyester, were compared for pos... more AbstractTwo types of composites, fiberglass/epoxy and fiberglass/polyester, were compared for possible application to natural gas pipelines. The properties of these composites in some corrosive med...
Journal of Thermal Analysis and Calorimetry, 2018
The estimation of solid-liquid phase equilibrium is important for the design, development, and op... more The estimation of solid-liquid phase equilibrium is important for the design, development, and operation of many industrial processes because of application in many manufacturing fields such as cosmetic, pharmaceutic, and biotechnology industries. In this work, we measured solid-liquid phase equilibrium of six fatty acid binary mixtures using the DSC technique and developed thermodynamic approaches for binary fatty acid mixtures to estimate melting temperatures as a function of mole fraction in solid-liquid phase equilibrium. Derivation of NRTL and UNIQUAC activity models was developed to predict melting temperatures and latent heat to achieve eutectic points of undecylic acid, pentadecylic acid, margaric acid, and stearic acid six pairwise binary mixtures. The fatty acids eutectic mixtures are appropriate for heat water systems, phase clothes, concrete, and other similar applications. The results showed low deviations from experimental data measured in this study.
Journal of Experimental Nanoscience, 2018
A nano enhanced phase change material, NEPCM, was prepared by the addition of carbon nanotubes, C... more A nano enhanced phase change material, NEPCM, was prepared by the addition of carbon nanotubes, CNTs, to butyl stearate. This study utilised single walled nano tube, multi-walled nanotube and modified multi-walled nanotube. Several kinds of surfactants were used to stabilise nano-particles in butyl stearate. Tetramethyl ethylene diamine (TEMED) was the best surfactant for enhancing the stability time of nano-fluid. The effect of CNTs concentration on the thermal properties of base fluid was studied and it was found that for all kinds of CNTs, the highest thermal conductivity of NEPCM was observed in weight fraction of 0.03. The modified-MWCNTs have the most enhancements in the butyl stearate thermal conductivity. It was found from differential scanning calorimetry tests, that modified-MWCNTs with 2 wt.% contents have the most effect on the latent heat of fusion of the base fluid. It was also observed that the SWCNT has a considerable effect on the melting point of PCM.
International Journal of Environmental Science and Technology, 2017
The carbon molecular sieves (CMSs) prepared by carbonaceous materials as precursors are effective... more The carbon molecular sieves (CMSs) prepared by carbonaceous materials as precursors are effective in CO 2 / N 2 separation. However, selectivity of these materials is too low, since hydrocarbon cracking for developing the desired microporosity in carbonaceous materials has not been done effectively. Hence, in this study, cobalt and nickel impregnation on the precursor was conducted to introduce catalysts for hydrocarbon cracking. Cobalt and nickel impregnation, carbonization under N 2 atmosphere, and chemical vapor deposition (CVD) by benzene were conducted on the extruded mixtures of activated carbon and coal tar pitch under different conditions to prepare CMSs. The best CMS prepared by carbon deposition on the cobalt-impregnated samples exhibited CO 2 adsorption capacity of 54.79 mg/g and uptake ratio of 28.9 at 0°C and 1 bar. In terms of CO 2 adsorption capacity and uptake ratio, CMSs prepared by carbon deposition on non-impregnated and cobalt-impregnated samples presented the best results, respectively. As benzene concentration and CVD time increased, equilibrium adsorption capacity of CO 2 decreased, and uptake ratio increased. Cobalt was found to be the best catalyst for benzene cracking in the CVD process. Keywords CO 2 separation Á CO 2 /N 2 mixture Á Carbon molecular sieve Á Metal impregnation Editorial responsibility: V.K Gupta.
Journal of Macromolecular Science, Part B, 2011
... Isotactic polypropylene (PP) is a common commodity plastic being of practical ... In the case... more ... Isotactic polypropylene (PP) is a common commodity plastic being of practical ... In the case of thegeometric mean model, the effective thermal conductivity of the composite is given by: ... Where. The values of A and Ф max were given for many geometric shapes and orientations. ...
Journal of Macromolecular Science, Part B, 2013
ABSTRACT The thermal conductivity (TC) of compression-moulded polypropylene (PP) and PP filled wi... more ABSTRACT The thermal conductivity (TC) of compression-moulded polypropylene (PP) and PP filled with 5–15% zinc oxide (ZnO) or calcium carbonate (CaCO3) nanoparticles, prepared by extrusion, was studied using a thermal conductivity analyzer (TCA). The effect of nanoparticle content and crystallinity on the thermal conductivity was investigated using conventional methods, including SEM, XRD, and DSC. The incorporation of nanoparticles improved the crystallinity and thermal conductivity simultaneously. The experimental TC values of the PP nanocomposites with different level of nanoparticles concentration showed a linear increase with an increase in crystallinity. The TC improvement in PP/ZnO nanocomposite was greater than that of PP/calcium carbonate nanocomposites. This fact can be attributed to the intrinsic, better thermal conductivity of the ZnO nanoparticles. Several models were used for prediction of the TC in the nanocomposites. In the PP/ZnO nanocomposites the TC values correlated well with the values predicted by the Series, Maxwell, Lewis and Nielson, Bruggeman, and De Loor models up to 10 wt%.
Materials Today Communications, 2021
Abstract In recent years, discharging a large amount of untreated oily wastewater has become an e... more Abstract In recent years, discharging a large amount of untreated oily wastewater has become an environmental issue because of the hazardous nature of its oil contents. Membrane separation can be considered an effective method for the treatment of these types of effluents. In this study, polymeric membranes were synthesized to separate oil/water emulsion in Esfahan’s Mobarakeh steel company’s effluent, Iran. The membranes were prepared based on polylactic acid (PLA) physically blended with Polybutylene succinate (PBS), polypropylene carbonate (PPC), and polyhydroxybutyrate (PHB) biopolymers with and without silica nanoparticles (SNPs). Prepared membranes were characterized using methods such as atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), and X-ray diffraction analysis (XRD). An experimental membrane module was also made to evaluate the filtration separation performance of membranes. The results showed that the membranes have suitable properties such as porosity and thermal stability. The membrane containing SNPs showed better separation performance, so that the amount of oil&grease (O&G), manganese, iron, total dissolved solids (TDS), and turbidity in the feed, were removed by 98.6%, 14.17%, 22.56%, 11.33%, and 89.15% respectively, using this membrane.
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Papers by Mohammad Hassan Vakili